1. Field of the Invention
This invention relates to a double containment pipe assembly for conveying fluids and, more particularly, a housing for use in the system which enables ready assembly and disassembly of the system in modular sections.
2. Description of the Prior Art
This invention has particular utility in the conveyance of hazardous or toxic fluids such as are often found in heavy industrial facilities. However, while the invention has particular application to the conveyance of hazardous or toxic fluids, it can be used with any type of fluid and many types of gases which must be conveyed in quantity from one place to another.
Hazardous fluids cannot be routinely conveyed in open top drainage channels, but instead in enclosed pipe or conduits. Recognizing that such pipes and conduits can leak because of manufacturing defects, excessive pressure, corrosion or other reasons, prior art double containment systems generally involve the placement of a relatively small fluid carrying closed-wall conduit within a larger closed-wall conduit which does not carry fluids except in the event of a leak of liquid carried by the inner conduit. The smaller conduit is supported by resting directly on the lower, inner wall of the outer conduit, or by use of a centering device that is positioned between the inner and outer conduits.
While the above-described system will perform adequately to prevent leakage of hazardous fluids into the environment from the inner conduit, repairing the leak in the inner conduit is expensive and time consuming. In many cases, the inner and outer conduits are hundreds of feet long and are formed either of seamless extruded conduit or conduit formed of relatively long segments. Since both conduits are closed-wall, the outer conduit must be penetrated to determine the location of the leak in the inner conduit. In some cases, the inner conduit must be disconnected and physically removed from the outer conduit. In other instances, the outer conduit must be penetrated at intervals along its length to determine the position of the leak. Even then, further damage to the outer conduit must take place in order to remove and/or repair the inner conduit and return it to use.
The invention described in this application provides all of the safety and security of a double wall containment system formed of inner and outer closed-wall conduits, while permitting easy access to the inner conduit to determine the location of a leak for repair, and the removal of the inner conduit section to repair the leak.